Blade wheel ship propeller



March 5, 1968 W. BAER Filed Feb. 16, 1967 Fig.

compressed air 23 compresed air 5 l6 I I l2 fi United States Patent Ofiiice 3,371,719 Patented Mar. 5, 1968 4 Claims. 01. 170-146) ABSTRACT OF THE DISCLOSURE The present invention relates to a blade wheel ship propeller including a housing, a hollow shaft in said housing, a wheel body including propeller blade pivots drivingly connected to said hollow shaft to be driven thereby, and a propeller well, in which first sealing means are interposed between said housing and said hollow shaft while second sealing means surround said propeller blade pivots for sealing the same toward the outside water. The said wheel body and said housing together form a compressed air receiving and storing vessel adapted to be connected to a source of compressed air, while pressure control means communicating with the interior of said vessel is provided for controlling the pressure therein so as to maintain the same in said vessel above the pressure of the water at the immersing depths of the propeller.

The present invention relates to blade wheel ship propellers. With blade wheel ship propellers, particular atten-' tion has to be paid to sealing the propeller wheel body comprising the blade driving linkage system and the bearings for the blades against the entry of water at the blade bearings. Furthermore, particular attention has to be paid-to sealing the so-called propeller housing, housing the hollow shaft and the driving gears therefor, against the entry of water from the propeller well. The greater the structural depth, the greater will be the danger that water will through the seals enter the interior of the wheel body and will pass into the propeller housing or into the interior of the ship through the so-called seep-age water drain. According to a relatively recent suggest-ion as set forth in US. Patent 2,988,154, the wheel body has been sealed against the entry of water by sealing the interior of the wheel body toward the outside and filling the same with oil under pressure, the pressure of which at least equals the static pressure of the water at the immersing depth of the propeller. The oil pressure is produced by a corresponding oil column which is formed by an elevated oil tank anda corresponding connecting conduit. With these frequently employed arrangements, there still remains the danger that water will enter the propeller housing which contains the hollow shaft and the driving gear therefor, or will enter the interior of the ship through the seepage water drain.

Another problem with blade wheel propellers consists in keeping the so-called wheel chamber in which the propeller rotates free from water. For relatively short structural depths of the propeller, a blade wheel pump may be used for this purpose during the operation of the propeller, which blade wheel pump is arranged at the outer circumference of the wheel body. When the propeller is located at greater depth so that higher water pressures are encountered, such pump, however, will assume too large dimensions. As replacement for the said blade wheel pump, it has been suggested according to German Patent 852,015 to arrange the propeller in a housing which is sealed at the top and at the sides and which is connected to a source of compressed air. More specifically, it has been suggested to arrange either the entire encased propeller including gear drive in said housing or only the as in the second instance a relatively expensive control device is unavoidable. Moreover, in both instances the interior chamber for the propeller will not be safe by the above mentioned steps.

.It is, therefore, an object of the present invention to provide a blade wheel ship propeller arrangement, which will overcome the above mentioned drawbacks.

It is another object of this invention to provide a blade wheel ship propeller arrangement which will safely protect the wheel body and the propeller housing as well as the interior of the ship against the entry of water and will maintain the propeller well free from water.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIG. 1 is a vertical section through a propeller with an outwardly journalled hollow propeller shaft.

FIG. 2 is a vertical section through a propeller with an inwardly journalled propeller shaft.

A blade wheel propeller with a Wheel body supported and driven by a hollow shaft and with a housing encasing said hollow shaft, and with seals between the housing and the propeller well and at the blade studs or pivots is, in conformity with the present invention, characterized primarily in that the wheel body and the housing are designed as air chambers and together with the propeller well are connected to a'source of compressed air. The blade wheel ship propeller according to the invention is furthermore characterized by the provision of a pressure guard for adjusting the air pressure in the said chambers somewhat higher than the respective water pressure. The above mentioned construction yields a considerable simplication over heretofore .kn-own constructions of the type involved because the awkward so-called oil damming-up seal becomes completely superfluous, and furthermore not only the wheel body but also the propeller housing and the propeller well will be made safe. The propeller shaft seals as well as the main seals are relieved so that -a propeller according to the invention can also work at greater water depth and thus under greater Water pressure.

A further advantage of the present invention consists in that a propeller designed in the above outlined manner can also be installed in such instances, e.g., in completely submerged bodies, in which the above mentioned elevated oil tank cannot be employed in view of the special space conditions.

With propellers, the main seal of which is located above the oil level in the propeller housing, this seal is designed in a manner known per se as double seal with a sleeve or the like sealing against the oil chamber and with a seal sealing against the propeller well, while the chamber be tween the two seals is connected to the source of compressed air in such a way that the compressed air passes through the seal at the side of the well into the propeller well and presses the water therein more or less out of the propeller well.

With the embodiment in which the said main seal between the propeller inner housing chamber and the propeller well is located above the oil level, a simple seal will do as main seal through which the air pressure can pass into the propeller well.

In contrast to herefore known designs, the propeller housing will, with a propeller according to the invention, no longer require a drainage opening so that the entry of water into the interior of the ship will no longer be possible. The blade wheel seals and the main seal are, as mentioned above, relieved so that only the gear shaft seal will have to absorb the total pressure drop. This seal, however, can in a manner known per se be designed refliably tight. According to a special suggestion of the present invention, this seal can be designed in a plurality of stages so that the pressure drop Will be distributed over a plurality of stages.

Referring now to the drawing in detail, the propeller shown in vertical section in FIG. 1 comprises a wheel body 2 provided with a hollow shaft 1. Wheel body 2 is by means of a thrust bearing 3 and a radial bearing 4 journalled in a fixed housing 5. A large bevel gear 7 is mounted on the upper end of the supporting body 6 which is connected to the hollow shaft 1 and fonms the thrust bearing vring. Bevel gear 7 together with the driving gear -8 is encased by the housing 5.

The supporting star 9 fastened in the housing and pertaining to the control stick 10 extends into the hollow shaft 1. The connections between the upper end of the control stick 10 and the adjusting servomotors 11 and between the lower end of the control stick 10 and the bearing stud 12 of blade 13 are omitted in order not unnecessarily to load the drawing, but may be of any standard design as disclosed, for instance, in U.S. Patent No. 2,753,006 and US. Patent No. 2,850,104. The blade shaft seals are designated with the reference numeral 14 whereas the main seal is designated with the reference numeral 15.

As will be seen from the drawing, the wheel body 2 is entirely and the housing 5 encasing the gears 7 and 8 is partially filled with oil. The oil level is indicated with the reference numeral 16. Connected to the upper portion of housing 5 is a compressed air conveying conduit 17 having a branch line 17a which leads into the space between the two sealing sleeves of the main seal 15. Any seepage water which might enter the main seal is discharged through a seepage water line 18 into a seepage water container 19. The compressed air which passes through the lower sleeve of the main seal into the propeller well 20 will press the water the level of which is indicated at 21 to approximately the level indicated by the reference numeral 22.

A pressure guard 23 which is adjustable in conformity with the respective immersing depth of the propeller is mounted on the upper portion of the housing 5.

With a design of the blade wheel propeller as illustrated in FIG. 1, it will be evident that at one side of the blade shaft seals there will prevail the water pressure in conformity with the immersing depth of the propeller, whereas on the inner side there will prevail a pressure somewhat above said first mentioned pressure. It will also be evident that the upper sleeve of the main seal is completely relieved because at both sides thereof the same pressure prevails.

FIG. 2 shows a blade wheel propeller according to the invention journalled on the inside. Those parts of the propeller which correspond to the parts of FIG. 1 have been designated with the same reference numerals as in FIG. 1. However, with the embodiment of FIG. 2, the main seal 15 is located between the compressed air chamber of housing 5 and the propeller well 20.

It is, of course, to be understood that the present invention is, by no means, limited to the particular embodiments illustrated in the drawing but also comprises any modifications within the scope of the appended claims.

W'h at I claim is: I

1. A blade wheel ship propeller which includes: a housing, a hollow shaft rotatably journalled in said housing, a wheel body including propeller blade pivots drivingly connected to said hollow shaft to be driven thereby, a propeller well surrounding said wheel body, first sealing means interposed between said housing and said hollow shaft, second sealing means for sealing said propeller blade pivots with regard to the outside water, the interior of said wheel body and said housing communicating with each other and forming a compressed air receiving and storing vessel, conduit means communicating with said vessel and adapted to be connected to a source of compressed air, and pressure control means communicating with the interior of said vessel to control the pressure therein for maintaining the pressure in said vessel above the pressure of the water at the immersing depth of said propeller.

.2. A blade wheel ship propeller according to claim 1, in which said housing is partly filled with oil, and in which said first sealing means is located at a level lower than the oil level in said housing, said first sealing means being formed by two sealing rings arranged one above the other in vertically spaced relationship to each other, the space defined by and between said two sealing rings communicating with said conduit means.

3. A blade wheel ship propeller according to claim 1, in which said housing is partly filled with oil, and in which said first sealing means is located at a level higher than the oil level in said housing, the interior of said propeller well communicating with said conduit means through said first sealing means.

4. A blade wheel ship propeller according to claim 1, in which said propeller well communicates with a source of compressed air.

References Cited UNITED STATES PATENTS 2,988,154 6/1961 Hub 146 FOREIGN PATENTS 930,674 7/1955 Germany.

EVERETTE A. POWELL, JR., Primary Examiner. 

